In $Scoliodon$,what type of fertilization is observed?

In which animal is the caudal fin heterocercal (asymmetrical)?

Which of the following statements are not true about shark?
$a$. The skin is tough and covered with placoid scales
$b$. They possess a swim bladder which regulates buoyancy
$c$. The tail of shark is heterocercal
$d$. Ampulla of Lorenzini present in the snout of shark is a thermoreceptor.
$e$. It has five pairs of gill slits covered by operculum

Heterocercal tail is found in

Fishes have very poor sense organs for:

Which sensory organ is found as a unique feature in fishes?